Layton AC, Smartt AE, Chauhan A, Ripp S, Williams DE, Burton W, Moser S, Phillips J, Palumbo AV, Sayler GS
In 1996, the first EPA sanctioned release of a recombinant microbe (Pseudomonas fluorescens HK44) into the
subsurface soil environment was initiated in a replicated semi-contained array of soil lysimeters. With an aim to
access the survivability/environmental fate of HK44, soil sampling was performed 14 years post release. Although
after extensive sampling culturable HK44 cells were not found, qPCR and metagenomic analyses indicated that
genetic signatures of HK44 cells still persisted in the soils, with genes diagnostic for the bioluminescent transposon
carried by strain HK44 (luxA and tetA) being found at low concentrations (< 5000 copies/g). Additionally, metagenome
analysis of lysimeter 2 using amplicon pyrosequencing showed that Burkholderia was more abundant in the sample
extracted before storage at 4°C than after storage at 4°C (79% and 5.6% Burkholderia sequences, respectively).
Layton AC, Smartt AE, Chauhan A, Ripp S, Williams DE, Burton W, Moser S, Phillips J, Palumbo AV, Sayler GS. 2012. Ameliorating risk: Culturable and metagenomic monitoring of the 14 year decline of a genetically engineered microorganism at a bioremediation field site. OMICS Journal of Bioremediation and Biodegradation S1:e009. doi: 10.4172/2155- 6199.S1-009.